Compilare: user.cpp:3: warning: ISO C++ forbids declaration of 'main' with no type user.cpp: In function 'int main()': user.cpp:41: warning: format '%ld' expects type 'long int', but argument 3 has type 'int' user.cpp:7: warning: unused variable 'm' user.cpp:7: warning: unused variable 'x' user.cpp:7: warning: unused variable 's' user.cpp:7: warning: unused variable 'sp' user.cpp:7: warning: unused variable 'valid'